do not set "Transfer-Encoding: chunked" for HEAD requests

src/http/modules/ngx_http_chunked_filter_module.c

diff --git a/src/http/modules/ngx_http_chunked_filter_module.c b/src/http/modules/ngx_http_chunked_filter_module.c
index 3cc20eb..846053f 100644
--- a/src/http/modules/ngx_http_chunked_filter_module.c
+++ b/src/http/modules/ngx_http_chunked_filter_module.c
@@ -53,7 +53,8 @@
     if (r->headers_out.status == NGX_HTTP_NOT_MODIFIED
         || r->headers_out.status == NGX_HTTP_NO_CONTENT
         || r->headers_out.status == NGX_HTTP_CREATED
-        || r != r->main)
+        || r != r->main
+        || (r->method & NGX_HTTP_HEAD))
     {
         return ngx_http_next_header_filter(r);
     }